This invention relates to a cooling device for a power component such as an IPM (Intelligent Power Module), a rectifying diode and a shunt resistor mounted on a board within e.g. servo-amplifier.
Where heat dissipation is attempted for power components using a heat sink, a conventional power component cooling device is designed so that several power components are arranged on a surface of the heat sink (for example, see Patent References 1 and 2).
[Patent Reference 1] JP-A-2003-152368
[Patent Reference 2] JP-A-2002-184920
The invention described in Patent Reference 1 intends to effectively dissipate the heat generated from a high heat-generating electronic member outside a case. For this purpose, a circuit board on which a plurality of electronic components are mounted is housed in the case. Among these electronic components, a high heat-generating component(s) having a high heating value and a low heat-generating component(s) having a low heating value are classified. And between the high heat-generating electronic component and the case, a heat-conductive member is individually located to connect them so that only the high heat-generating electronic component is mounted on the one end of the circuit board and only the low heat-generating electronic component is mounted on the other end thereof opposite to the one end.
The invention described in Patent Reference 2 provides a heat dissipating device capable of giving high heat dissipating effect while preventing overload for a heat dissipating component such as Central Processing Unit. For this purpose, two thin metallic heat dissipating plates having elasticity are stacked and a high heat-conductive rubber is provided between the CPU and the metallic heat dissipating plates.
The conventional power component cooling device described in these Patent References 1 and 2 is commonly shown in FIGS. 3 and 4.
FIG. 3 is a top view of the conventional power component cooling device and FIG. 4 is a front view thereof.
In FIGS. 3 and 4, reference numeral 11 denotes a unit constituting component that is a heat sink equipped with cooling fins 11a on the rear surface; 12 a power board secured to the heat sink; 13 a high heat-generating power component such as the IPM mounted on the power board 12; 15 a middle heat-generating component such as a rectifying diode mounted on the power board 12; and 16 another middle heat-generating power component such as a shunt resistor mounted on the power board 12. In this configuration, cooling for the respective power components is carried out through the heat sink in intimated contact with the heat dissipating faces of the power components.
However, the conventional power component cooling device presented a problem that in carrying out the heat dissipation for the power components using the heat sink, a large space is required because several power components are arranged on the one surface of the heat sink, thus increasing the size of the heat sink.
It also presented a problem that since the high heat-generating component and middle heat-generating component are arranged on the same surface, a uniform temperature distribution cannot be obtained, thus making it impossible to use the capability of the heat sink effectively.